Ingward

"Well, this is a surprise. I don't get many visitors, except for ghosts. Do you have some business here? My name is Ingward. I'm an old man, bound to these parts. But I don't mind a chat. I may even be of some help."

Ingward is mentioned to be one of the three sealers who entered the New Londo Ruins in order to flood the area and stop the Four Kings and the Darkwraiths. The other two tired of their duty and left the area, making Ingward the only remaining sealer. Not much more is known about the sealers other than the fact that they were known also for their healing powers, hence their crimson robes.

Killing Ingward early on the PC version can sometimes result in a glitch where he will not drop the key to the seal, rendering that save useless because the key can then be obtained no other way.

Despite helping to flood New Londo to protect Lordran from the Darkwraiths, Ingward will not become hostile if the player places the Lordvessel for Kaathe. Even if the player joins the Darkwraith covenant, he will still be friendly and provide his services.

Well, this is a surprise. I get few visitors, save for ghosts. You have... the Lordvessel. Very impressive. I know exactly what your intentions are. You seek the Four Kings whom I guard over. This is the key to the seal. The Four Kings slumber in the deepest chamber of the ruins. Use this key to break the seal and open the floodgates. ...Oh and do not forget... The Darkwraiths reside in a dark void called the Abyss. But the Abyss is no place for ordinary mortals. Although long ago, the knight Artorias traversed the Abyss. If you can find him, and learn from him, the Abyss may prove surmountable.

Introduction (without Lordvessel)

Well, this is a surprise. I get few visitors, except for ghosts. Do you have some business here? My name is Ingward. I'm an old man, bound to these parts. But I don't mind a chat. I may even be of some help.

Greetings x1

Hello there. What is it? The key to the seal is now in your hands. I will help you in any way possible.

Greetings after defeating the Four Kings

...Magnificent. You defeated the Four Kings. Impressive, even for a bearer of the Lordvessel. And with this, my purpose is exhausted. I have not seen the sun for a long time. Perhaps I could do with a change...

Greetings x2

Hello again. How are you?

Greetings x3

Hello, there. Where have you been? I'm glad to see you well. How can I be of assistance.

Talk x1

New Londo was sacrificed to contain the Darkwraiths. Mark my words. The Darkwraiths are the enemies of man, and any living thing that has a soul. They were never meant to roam again.

Talk x2

I am the Guardian of the Seal. I watch over the Four Kings, the masters of the Darkwraiths. The Darkwraiths are the enemies of man, and any living thing that has a soul. They were born in New Londo, and that is where they perished; the entire city was sacrificed to contain them. ...For that is how great a threat they were...

Back at Firelink

Oh, hello. The sunlight made me wince, and now I've come back to this dark hole! So what brings you here? I will help you in any way I can.

Greetings at Firelink

Oh, hello. What is it? I will help you in any way that I can.

Attacking him

Sigh... You are no different from the rest... So be it! I am Ingward, the guardian of the seal. Prepare to meet your doom!

The following is content that is present within the code of Dark Souls, but not actually implemented in the game. Text was found from a text dump which can be found at: http://pastebin.com/hA42TwK8

Click to see Removed Content (Contains Spoilers)

From the code it appears Ingward would've tested the player before giving up the Key to the Seal. He would've had the player kill a specific Darkwraith (probably Undead King Jar-Eel) before giving the key up. It is suggested in the following text:

Speaking to him with the Lordvessel

Oh, hello. You've acquired the Lordvessel, have you? Very impressive. I know exactly what your intentions are. You seek the Four Kings whom I guard over. And yes, I do have the key to the seal. But before I give it up, there is something I must ask. Do you see the great hall that stands before you? Atop it, you will find a Darkwraith, a servant of the Four Kings. Show me that you can defeat it. As guardian of the seal, it behoves me to test your strength. For if you cannot defeat the Darkwraith, you will be no match for the Four Kings. Even if Frampt has chosen you. Even if you are the bearer of the Lordvessel.

Speaking to him before killing the Darkwraith

Hate to ask, really. But I am the Guardian of the Seal. I have seen too many lives wasted over the eons. So, I had no choice but to test your mettle.

Speaking to him after killing the Darkwraith

You, you have defeated the Darkwraith! Very good, indeed. I can certainly trust you. This is the key to the seal. The Four Kings slumber in the deepest chamber of the ruins. Use this key to break the seal and open the floodgates. ...Oh, and do not forget... The Darkwraiths reside in a dark void called the Abyss. But the Abyss is no place for ordinary mortals. Although long ago, the knight Artorias traversed the Abyss. If you can find him, and learn from him, the Abyss may prove surmountable.